Hey, so I was here two weeks ago, worrying about my grandma having alzheimers, well she is alright, but now I worry about myself, but before freaking out, I wanted to ask is it even possible to get alzheimers at 18 ?

It is highly unlikely that you have alzheimers at 18 of age.I had/have the same fear but read that if a person starts to get symptoms at 50 years old its considered very young. You have nothing to worry about at all :)